TUNING UPDATE

I've done much experimentation with different Lambda map configurations. But most to no effect as far as getting more fuel into my turbo M30 at 4200rpm and above. I believe that the DME is decreasing injector duty cycle(IDC) as RPM rises so theres no possibility of puddling on the back hat of the valves. As we know, the M30 is batched injector firing system. 3 inj's are fired at once.

There seems to be a limit on how much IDC you can get with changing the Lambda map values. It seems the maximum is determined by other variables used by the code.

Next, I've tried installing 42lb/hr injectors. In doing so, I have changed what I believe to be either the injector size constant or AFM scaling factor. Either way, it does work, and I was successful in getting the 42lb'rs to work well. Unfortunately, there are some problems with the inj's I have. I get a too much detonation at boost levels I could run with the 31lb inj's just fine. This tells my there are flow issues with the 42lb sets of injectors I have. I'm going to send these out and have them sonicly cleaned, flow tested and sycronize the flow across all 6. I'll update when I get this done and inj's re-installed. There are no problems with minimum duty cycle issues with this inj size. This was also confirmed by other sources, one being that tuners put 80lb inj's in Subaru WRX's, and they have puny 2.5L engines!

Also, what Dinan has done with the system is completely in focus now. When I first looked at what Dinan had in the software, I was very confused. Dinan had changed the inj size constant to run richer with the 31lb inj's? Huh? Wouldn't it run real rich?? Well, I was not taking into consideration that Dinan had adjusted the AFM spring tension tighter, effectively leaning the system a great deal. But, this is necassary to tune the car properly. The Motronics works best if the EFI system can measure the entire air flow(mass) range by the AFM. If the AFM was not adjusted in this manner, it would max out at 3k rpm's under boost. Not very good. So Dinan tightened the spring to a point that the AFM could measure the entire air flow range from idle to 13psi @ 5100rpm making 360hp. The tension to get there meant richening the system past what was set at the factory, even with inj's that are 72% larger than stock. I used 20h for the 41lb inj's(up in value for leaning, down for richening). For the non-engineer, 19h is 25d-decimal and 20h is 32d.

And, I have recieved many ROMs to compare from friends. The latest is DukeS's Hartge tuned ROM. This was very enlighting. Hartge's software is very interesting. Hartge actually went a step farther and changed the IDC matrix values. To further expand, see this pic, the US stock values for IDC are on the vertical axis: 8%, 12%, 16%, 20%, 24%, 28%....to 54%. In the Hartge's ROM the IDC values are 12% on up to 67%! They have increased the IDC higher due to the fact that their engine makes 240hp vs US 181hp and flows a lot more air than the US version(also doesn't use a catalyst). Hence they need more fuel to go with that air. More below.

I will install these new IDC values in my car in the next day or so to see if it works for a US car! Also, Hartge has deleted large blocks of software from the ROM, my guess is that since this is a Euro car that has no cat or O2, they don't need the code for emissions and Lambda control, like a US car. So all that code can be deleted. I'll update again as more info comes in.

RussC